CN-119750757-B - Method for enhancing Fenton-like fluidized bed reaction efficiency by intelligent magnetic control

Abstract

The invention belongs to the technical field of environmental engineering, and particularly relates to a method for enhancing Fenton-like fluidized bed reaction efficiency by intelligent magnetic control. Specifically, the customized composite magnetic particles are placed in a columnar Fenton-like fluidized bed reactor with an electromagnetic coil array distributed around, the percarbonate activated by the ferric aluminum phosphate is used as an oxidant, and magnetic fields with different directions and intensities are applied to the magnetic particles by using the electromagnetic coil array, so that the magnetic particles guide fluid to form a required flowing form, and the high-precision control of a fluid flowing path and a mixing process is realized, thereby achieving the purposes of fully mixing the composite magnetic particles with percarbonate ions, efficiently generating secondary oxidants such as hydroxyl free radicals, carbonate free radicals, superoxide anion free radicals and the like and efficiently degrading pollutants.

Inventors

• YIN LIFENG
• GUO TAO
• YANG BOXUAN
• ZENG YUXIN
• LIN YUANZHONG

Assignees

• 北京师范大学

Dates

Publication Date

20260508

Application Date

20250116

Claims (5)

1. 1. A method for enhancing Fenton-like fluidized bed reaction efficiency by intelligent magnetic control is characterized by comprising the following steps: Step 1, constructing a closed Fenton-like fluidized bed reactor, wherein the inner diameter of the closed Fenton-like fluidized bed reactor is 0.5-2 m; a height of 3 to 6 m, ensuring sufficient reaction space and material residence time; the reactor is of a cylindrical structure with an arc bottom, which is beneficial to the collection and discharge of solid particles; the bottom of the reactor is provided with a liquid flow distribution plate, a porous ceramic material with an aperture of 10-30% and a pore diameter of 0.5-2 mm for promoting the full mixing of liquid and solid particles, an overflow port is arranged at the top for discharging the treated liquid and preventing foam from overflowing, the reactor wall is made of 316L stainless steel, is internally lined with polytetrafluoroethylene coating and has a thickness of 0.5-mm, the reaction volume is designed between 1-20 m 3 according to the treatment capacity, a main feed port is arranged at the lower part of the side surface of the reactor and is close to the bottom for feeding the feed liquid into the reactor and is at a position 10-cm from the bottom, the diameter is 80 mm, an auxiliary feed port is arranged beside the main feed port and is used for feeding percarbonate oxidizer, a discharge port is arranged below the top overflow port and is connected with the top overflow port, continuous discharge is realized in an overflow mode, a heat exchange system is integrated in a shell jacket, the circulating cooling water or hot water flow rate is 1-5-m 3 /h, the heat exchange area is 0.5-2-m 2 , the reaction temperature is ensured to be stabilized within a range of +/-1 ℃, the exhaust hole is arranged at the top of the reactor, the diameter is mm, an automatic pressure regulating valve is arranged at the bottom of the side surface of the reactor is close to the bottom, the bottom of the reactor is arranged at the position of 10-50-cm, the bottom is convenient for realizing the intermittent and the continuous flow-type, the solid flow-phase change system is in a constant-phase change system is arranged in a constant-change state, the pressure-change system is arranged at the bottom, and the bottom of the solid-phase converter is in a constant-change system is in a constant state, and a constant-pressure state, the pressure-constant-flow system is in a constant state, and a constant-pressure system is arranged in a constant state, and a constant flow system is in a constant state and a constant pressure system is arranged is in a constant control system is arranged in a constant and a pressure and a constant pressure and a constant pressure and a pressure control system is in a constant control system is in a pressure and a constant pressure and a pressure in a pressure and a, the device comprises a reactor, a controllable magnetic catalyst, a magnetic coil, a metering pump, a magnetic field controller, a magnetic control system and a control system, wherein the distance between each layer is 10-20 cm, the coil is formed by winding a copper wire, the number of single-layer turns is 100-500, the wire diameter is 0.5-1 mm, the electromagnetic coil is connected to a controllable power supply and supports a direct current or alternating current power supply mode, the voltage range is 0-50V, the coil array generates a magnetic field with the intensity of 0.1-1T, the direction is controlled by adjusting the current phase, the special fluidization mode of the reactor is based on an intelligent magnetic control technology, the controllable magnetic field with the magnetic field intensity of 0.1-1T is generated by the external electromagnetic coil to act on a system containing the magnetic catalyst, when the magnetic field direction is perpendicular to a bubble ascending path, the gas-liquid-solid three-phase contact efficiency can be remarkably enhanced, the catalytic performance can be regulated, the feeding mode adopts the metering pump to precisely control the input quantity of raw materials, and the proportion of reactants is ensured to be constant; Step 2, preparing magnetic particles with regular hexagonal prism-shaped structures, wherein the magnetic particles are used as reaction catalysts, the particle size range is 1-5 mm, the magnetic core is iron-nickel-tungsten alloy, the mass ratio of iron to nickel to tungsten is 7:1:0.02-9:1:0.02, tricyclopentadiene samarium is doped as a stabilizer, sesbania powder is used as an adhesive, and the magnetic particles are prepared by a rolling method; Step 3, selecting percarbonate as Fenton-like oxidant, wherein the mass ratio of the initial adding amount of the percarbonate to the feed liquid is 1:100-1:1000, and simultaneously adding ferric aluminum phosphate with the mass ratio of the feeding liquid of 1:10000-1:100000 as an activating agent, quantitatively mixing with the feed liquid through a metering pump, and adjusting the adding frequency in real time according to the reaction process to ensure that the concentration of the percarbonate ions is maintained at an optimal level; Step 4, before starting the Fenton-like fluidized bed reactor, firstly setting the running condition of the reactor to be at 20-60 ℃, filling magnetic particles accounting for 10% of the internal volume of the reactor into the reactor as a reaction catalyst, firstly passing tap water with a certain flow rate through a main feed inlet, keeping a magnetic particle suspension layer within 1/3 of the total liquid depth of the reactor to form a stable fluidization state, setting the pH value of feed liquid to be 3-11, gradually switching the pH value into feed liquid to replace tap water feed, synchronously introducing percarbonate feed from an auxiliary feed inlet, closely monitoring the height of the magnetic particle suspension layer in the process, keeping the upper interface of the magnetic particle suspension layer within 1/3 of the total liquid depth of the reactor, and being below the liquid level, and simultaneously avoiding abnormal phenomena of flooding, overpressure and aggregation; Step 5, monitoring the position and the speed of the magnetic particles through a built-in sensor, dynamically adjusting the current intensity and the phase of an electromagnetic coil by a closed loop feedback control system according to a preset algorithm to realize accurate control of the movement path of the magnetic particles, and applying a rotating magnetic field to enable the particles to move along a specific track when the mixing effect needs to be enhanced; Step 6, under the action of a magnetic field, the magnetic particles are fully contacted with percarbonate ions to generate hydroxyl free radicals, carbonate free radicals and superoxide anion free radicals, the free radicals are quantitatively analyzed by utilizing a fluorescent probe method and an electron paramagnetic resonance technology, the method for quantitatively analyzing the free radicals is a free radical quantitative detection method, the concentration of the free radicals is ensured to reach the optimal catalytic degradation effect, the detection range of the fluorescent probe method is 10 -9 -10 -6 mol/L, and the resolution of the EPR technology is better than 10- 12 mol/L; step 7, optimizing a fluid flow path and a mixing process, controlling the movement of magnetic particles by adjusting the intensity and the direction of a magnetic field, changing a liquid flow mode, applying a gradient magnetic field to enable the particles to gather to form micro vortex so as to promote local mixing, applying a uniform magnetic field to keep the whole fluidity, and combining an ultrasonic flowmeter and a laser Doppler velocimeter to monitor the flow field change so as to ensure the optimal mixing state; And 8, acquiring environmental parameters in the reactor in real time by means of a plurality of types of sensors including a temperature sensor, a pH value sensor and a dissolved oxygen sensor, transmitting all sensor data to a central controller, automatically adjusting working parameters of an electromagnetic coil after data analysis to form the closed loop feedback system, and automatically alarming and taking protective measures under abnormal conditions by the aid of a fault diagnosis function.
2. 2. The method for enhancing the Fenton-like fluidized bed reaction efficiency by intelligent magnetic control according to claim 1, wherein the electromagnetic coil in the step 1 further comprises an embedded permanent magnet to provide a static background magnetic field and enhance the effect of a dynamic magnetic field, the permanent magnet material is neodymium iron boron, the magnetic energy product is larger than 40MGOe, the working temperature ranges from-40 ℃ to +150 ℃, and stable operation under different environments is ensured.
3. 3. The method for enhancing the Fenton-like fluidized bed reaction efficiency by intelligent magnetic control according to claim 1, wherein the surface coating of the magnetic particles with regular hexagonal prism-like structures in the step 2 is polytetrafluoroethylene, and the thickness is 5-20 nm, so that the corrosion resistance and the lubrication performance of the particles are further improved, and the service life is prolonged.
4. 4. The method for enhancing the Fenton-like fluidized bed reaction efficiency by intelligent magnetic control according to claim 1, wherein the closed loop feedback control system in the step 5 is further integrated with a machine learning algorithm of a recurrent neural network for predicting the optimal motion track of the magnetic particles, and the recurrent neural network model is trained based on historical experimental data, so that a complex time sequence relationship can be identified, and the control precision is improved.
5. 5. The method for enhancing the Fenton-like fluidized bed reaction efficiency by intelligent magnetic control according to claim 1, wherein the method for quantitatively detecting free radicals in the step 6 further comprises the application of an online ultraviolet-visible spectrophotometer, the detection wavelength range of which is 200-800 nm, the sensitivity of which is better than 0.001 Abs, and the method can rapidly respond to the change of the concentration of free radicals, provide real-time monitoring data and assist in optimizing the reaction conditions.

Description

Method for enhancing Fenton-like fluidized bed reaction efficiency by intelligent magnetic control 1. Technical field The invention belongs to the technical field of environmental engineering, and particularly relates to a method for enhancing Fenton-like fluidized bed reaction efficiency by intelligent magnetic control. Aiming at the problems that the prior Fenton-like fluidized bed reactor has complex and fixed structure, poor adjustability, little improvement compared with the traditional Fenton technology, the method for enhancing the Fenton-like fluidized bed reaction efficiency by intelligent magnetic control is custom-designed so as to achieve the purposes of energy conservation, carbon reduction and high-efficiency pollutant degradation. 2. Background art The Fenton fluidized bed technology has obvious application value in the field of environmental pollution control, in particular to the treatment of high-concentration high-toxicity organic industrial wastewater. The Fenton fluidized bed can efficiently degrade refractory organic matters such as coking wastewater, printing and dyeing wastewater, pharmaceutical wastewater and the like by combining a fluidized bed technology with Fenton reaction. Research shows that the COD removal rate of the Fenton fluidized bed on the coking wastewater can reach 55% -65%, which is better than 40% of that of the traditional Fenton method. In the treatment of printing and dyeing wastewater, the Fenton fluidized bed can reduce COD from 953mg/L to 290mg/L, and simultaneously, the biodegradability of the wastewater is obviously improved. In addition, the Fenton fluidized bed is excellent in the aspects of treating landfill leachate, phenolic wastewater, electroplating wastewater and the like, and the generated hydroxyl radical (OH) oxidation-reduction potential is as high as 2.8V, and is inferior to fluorine, so that various toxic organic matters can be rapidly degraded. While Fenton fluidized bed has significant advantages in wastewater treatment, its structural complexity and efficiency problems limit its further popularization. Existing Fenton fluidized beds generally employ fixed structure designs, such as tower-bottom reactors, whose design layout, packing distribution and reaction cavity shape are often not adjustable, resulting in limited optimization of reaction conditions. In addition, the multiple field coupling effects inside the reactor are difficult to control accurately, for example, uneven flow field distribution can lead to local inefficiency of the reaction, while excessive chemical reaction field strength can trigger side reactions. These problems make the overall efficiency of the reactor difficult to break through, for example, some Fenton's fluidized bed iron sludge production is still up to 70% of that of the traditional Fenton's process, and H 2O2 utilization is low. Meanwhile, the existing reactor has poor expandability, is difficult to adapt to the reaction requirements of different scales and types, and the reaction efficiency is often obviously reduced in an enlarged experiment. These shortcomings indicate that the existing Fenton fluidized bed has significant defects in structure and performance, and needs to be improved through technical innovation. To improve the defects of Fenton fluidized bed, many research teams have actively explored in structural design and performance optimization. For example, chinese patent CN202139138U discloses an improved Fenton fluidized bed wastewater treatment device, by optimizing filler distribution and flow pattern, the uniformity and stability of reaction are remarkably improved, and the removal rate of COD is improved by 10% -20%. Fenton oxidation tower equipment is developed by Guangxi Boshi environmental protection technology Co-Ltd, a fluidized bed is formed through hydraulic conditions, and the fluidized bed reacts with a catalyst together, so that the wastewater purification efficiency is improved by more than 30%. The Fenton fluidized bed and intelligent control automatic dosing system combining technology is developed by Shandong environmental protection technology limited company, the pH value, the addition amount of H 2O2 and Fe 2+ are automatically regulated by monitoring oxidation-reduction potential change in real time, the consumption of H 2O2 is reduced by 10% -20%, the consumption of Fe 2+ is reduced by 50% -70%, the total sludge amount is reduced by 40% -50%, meanwhile, the COD removal rate is improved by 20% -30%, and the running cost is saved by 30% -50%. However, the current design and improvement does not involve the intrinsic innovation of the Fenton system, and the main problems are represented in the following three aspects: 1) The Fenton system still adopts the traditional operation modes of H 2O2 and Fe 2+, so that the mud yield is high, the efficiency is low, and the adjustability is poor; 2) The requirement on the pH value of the inlet water is high, and more sulfuric acid and